The present invention generally relates to dispersing material into the ground.
Materials such as fertilizer or other soil amendments are conventionally applied to the surface of the ground using a spreader or other similar device. Applying a material such as fertilizer to the ground surface limits the depth to which the fertilizer can penetrate the ground below the surface. Fertilizer dispersed above the ground is less likely to amend the soil at appreciable depths. To achieve deep fertilization, additional fertilizer must be spread over the ground surface which can become cost prohibitive. This is particularly true for soils that are less penetrable such as clay and when deep soil amendments are desired, e.g., to fertilize deep root systems.
Above the ground material delivery systems also increase the likelihood that the material being dispensed will run-off into nearby streams, lakes or other bodies of water before substantially penetrating the ground. Runoff containing fertilizer or other soil amendments applied to the ground surface increases water pollution. The Clean Water Act in the United States prohibits direct channeling of runoff into bodies of water to reduce water pollution caused in part by surface pollutants such as fertilizer or other soil amendments.
Some conventional fertilizer dispensing devices deliver fertilizer directly into the ground. One conventional subterranean device is a spike made of fertilizer material. Conventional fertilizer spikes are hammered into the ground and dissolve over time to deliver fertilizer below ground. However, spikes made of fertilizer are relatively short and are difficult to drive into hard ground, thus limiting their use to workable soils and relatively short depths. Further, conventional fertilizer spikes are not refillable since the entire spike is made of fertilizer which eventually dissolves completely into the ground.
Other conventional subterranean fertilizer delivery systems have a hollow plastic spike with a cap covering the spike. Some cap types are removable so that fertilizer may be periodically re-added to the hollow spike. Conventional hollow fertilizer spikes are hammered into the ground, allowing the fertilizer contained therein to dissolve gradually over time into the ground through holes formed in the spike. Conventional hollow fertilizer spikes are also relatively short and thus have limited soil penetration depth. Thus, the soil is amended at only short depths. Further, the hollow spikes tend to be narrow, reducing the amount of lateral dispersion of fertilizer from the spike into the ground. Although some conventional hollow fertilizer spikes are refillable, they are difficult to locate after placement in the ground due to their narrowness. Also, it is difficult to re-fill the narrow spikes without spilling fertilizer.